To use Mathcad’s surface plot operator to draw parametric surface plots:
• Type the names of three matrices having the same number of rows and columns into the placeholders at the bottom of the surface plot.
• Mathcad interprets these three matrices as the X-, y-, and z-coordinates of points on a surface and draws this surface from the viewing angle prescribed by the Rotation and Tilt settings.
The underlying parameter space is a rectangular sheet covered by a uniform mesh. In effect, the three matrices map this sheet into three-dimensional space. For example, the matrices X, Y, and Z defined in Figure 22-2 carry out a mapping that rolls the sheet into a tube and then joins the ends of the tube to form a torus
Resizing surface plots
To change the size of a surface plot, follow these steps:
• Click in the surface plot to select it.
• Move the mouse pointer to one of the three handles along the edge of the surface plot. The pointer will change to a double-headed arrow.
• Press and hold down the mouse button. While holding down the button, move the mouse. The surface plot region will stretch in the direction of motion.
• Once the surface plot is the right size, let go of the mouse button.
• Click outside the surface plot to deselect it.
Formatting surface plots
Mathcad provides many ways to change the way a surface plot looks. These can be categorized in four groups:
• Viewing characteristics: the type of plot being displayed; the perspective or point of view from which you see the surface; how “bumpy” the surface looks; and the presence or absence of borders, enclosing boxes, axes, and coordinate planes.
• Color and line formatting: whether the z-coordinates of the surface are indicated by shades of gray or by color; whether the surface is opaque or transparent; and whether the surface patches form a smooth surface or form parallel patches.
• Axis formatting: whether to show tick marks or grid marks on each axis.
• Title characteristics: how the surface plot will display titles.
To change any of these plot characteristics, start with the 3D Plot Format dialog box:
• Choose Graphee Jl) Plot from the Format menu. Alternatively, double-click on .she plot itself. Mathcad brings up the 3D Plot Format dialog box. The View Page of this dialog box is shown below. The remaining three tabs take you to three additional pages.
• If necessary, click the tab for the page you want to work with.
• Make the appropriate changes in the dialog box.
• To see the effect of your changes without closing the dialog box, click “Apply.”
• When you’re finished, close the dialog by clicking “OK.”